Why it took a long time to build that tiny link preview on Wikipedia (via) Wikipedia now shows a little preview card on internal links with an image and summary paragraph of the linked page. As a Wikpedia user I absolutely love this feature—and as an engineer and product designer, it’s fascinating to hear the challenges they overcame to ship it. Of particular interest: actually generating a useful summary of a page, while stripping out the cruft that often accumulates at the beginning of their text. It’s also an impressive scaling challenge: the API they use for this feature is now handling more than 500,000 requests per minute.